docs: def _readse(self, pos):
          """Return interpretation of next bits as a signed exponential-Golomb code.
  
          Advances position to after the read code.
  
          Raises ReadError if the end of the bitstring is encountered while
          reading the code.
  
          """
          codenum, pos = self._readue(pos)
          m = (codenum + 1) // 2
          if not codenum % 2:
              return -m, pos
          else:
              return m, pos